Wear protection elements for planar or curved surfaces exposed to abrasion

ABSTRACT

A wear protection element adapted to varied planar and curved surfaces, made from an elastomer, preferably natural or synthetic rubber, and having sheet-like body member and projections or ridges integral with and projecting from the surface of the sheet-like body member. The projections which may segmented or continuous ridges have at least two side surfaces with different angles of inclination relative to the surface of the sheet-like member having the projections or ridges thereon.

United States Patent 1191 Persson 1 1 WEAR PROTECTION ELEMENTS FORPLANAR OR CURVED SURFACES EXPOSED TO ABRASION (75] Inventor: Bo KlasGerhard Persson.

Trelleborg, Sweden [73] Assignee: Trelleborgs Gummifabriks Aktiebolag,Trelleborg, Sweden [22] Filed: Nov. 22, 1972 [2]] Appl. No.: 308,858

Related U.S. Application Data [63] Continuation-in-part of Ser. No.98,295, Dec. 15,

1970, abandoned.

[52] U.S. Cl. 156/71; 156/137; 156/297; 161/116; 198/198; 241/182;241/294;

241/300; 24l/D1G. 30

[51] Int. Cl. B321) 31/00 [58] Field of Search l61/116,123,145, 165;156/71, 297, 299, 137; 241/103, 182, 183,

294, 300, DIG. 30; 198/198 [56] References Cited UNITED STATES PATENTS1,853,249 4/1932 Ainley .1 241/DlG1 30 1451 July 22, 1975 2,004,5736/1935 Galley et al 241/DIG. 30 2,064,554 12/1936 Mahoney et a1.24l/D1G. 30

2,069,720 2/1937 Harvey 1 1 1 161/123 2,366,209 1/1945 Morris l 161/2392,784,835 3/1957 Dixon 161/123 3,001,730 9/1961 Daman 241/183 3,085,6764/1963 Hinchcliffe 198/198 3,378,209 4/1968 Crocheron 241/182 PrimaryExaminerGeorge F. Lesmes Assistant Examiner-Stanley S. SilvermanAttorney, Agent, or Firm-Browne, Beverid'ge, DeGrandi & Kline {5 7}ABSTRACT A wear protection element adapted to varied planar and curvedsurfaces, made from an elastomer, preferably natural or syntheticrubber, and having sheet-like body member and projections or ridgesintegral with and projecting from the surface of the sheet-like bodymember. The projections which may segmented or continuous ridges have atleast two side surfaces with different angles of inclination relative tothe surface of the sheet-like member having the projections or ridgesthereon.

7 Claims, 7 Drawing Figures WEAR PROTECTION ELEMENTS FOR PLANAR ORCURVED SURFACES EXPOSED TO ABRASION This is a continuation-in-partapplication of my earlier application Ser. No. 98.295 filed Dec. 15,1970, now abandoned.

The surface of chutes, unloading stations for conveyors, baffle walls,screens and the like are exposed to wear or abrasion by material flowingalong the surfaces. To increase the wear resistance of the surfacesprior art has already suggested the use of so-called wear protectionelements of natural or synthetic rubber and other elastomers. Forcertain purposes, prior art has also shown a retardation or agitation ofthe material flowing along the surfaces in question, and to satisfythese purposes prior art has arranged projections that are eitherseparate from or integral with the wear protection element; as a rulethese projections have been in the shape of elongated ridges or ribs.These projections, ridges or ribs, however, are exposed to a morevigorous wear or abrasion than the remaining wear protection element,and it has therefore been a long-felt desideratum to improve the wearingstrength of such means. To this end, prior art has suggested to use ofsheathings of for instance cemented carbides or ceramic at the mostexposed points. Applicant has also found that the best wearing strengthof the projections and thus of the entire wear protection element can beattained by taking measures such that the abrading material will stikethe surface of the wear protection element at such an angle of incidencethat the angle made between the wear protection element surface struckby a particle of abrading material and the force resultant with whichthe particle upon sliding movement or impact acts upon said surface iseither within the range of -5 or 70-90 when the wear protection elementis formed by an elastomer, particularly natural and synthetic rubber. Ifthe angle in question were within the approximate range of lO-30 theelastomeric material would, however, be very rapidly worn or abraded. Itshould be mentioned here that within the ranges of 7 1 0 and 3050 steelnormally has a higher wearing strength than wear-resistant rubber,whereas wear resistant rubber within the above mentioned ranges of 05and 70-90 is considerably more wear resistant than steel. Therefore, thepresent invention, while exploiting said insight into the wearingstrength of elastorneric bodies, has for its object to permitmanufacturing wear protection elements as standardized piece goods withas large a usefulness as possible. To attain this, the wear protectionelement according to the invention is formed with projections or ridgesprojecting from that surface or the wear protection element which isexposed to abrasion, and the free ends of said projections or ridges asviewed in an elevation at right angles to the surface of the wearprotection element, terminate within the base surface of the projectionsor ridges but is located eccentrically in relation to said base surfaceso that the projections or ridges will have at least two oblique lateralsurfaces with different angles of inclination relative to the surface ofthe wear protection element having the projections or ridges thereon.

Some embodiments of wear protection elements according to the inventionwill be described in detail hereinbelow with reference to theaccompanying drawing in which:

FIG. 1 is a cross section of a fluted wear protection element accordingto the invention;

FIG. 2 shows the fluted side of said wear protection element;

FIG. 3 shows another embodiment of the wear protection elementillustrated in FIG. 1;

FIG. 4 shows a plan view of an oblique rectangular, possibly truncatedpyramid which forms one of a great many projections which are arrangedin an optional pattern on the surface of another embodiment of the wearprotection element according to the invention;

FIG. 5 shows a section of line VV in FIG. 4;

FIG. 6 shows a section on line VlVl in FIG. 4;

FIG. 7 exemplifies the use of the wear protection element illustrated inFIG. I.

The wear protection element illustrated in FIG. I is made of anelastomer, particularly natural or synthetic rubber, which has beenmixed with the customary additions such as active carbon black, e.g.HAF, SAF or ISAF black, and the like to obtain as especially highabrasion strength. The wear protection element has ridges 10 and valleysor flutes 11 which at the manufacture of the wear protection element byextrusion are in the form of continuous ridges and valleys or flutes.According to the invention, the two longitudinal side surfaces 12, 13 ofthe ridges or ribs have different angles of inclination relative to themain plane of the wear protection element so that said wear protectionelement, upon reversal, can provide two different angles of incidencefor the material which, either for sliding movement or impact, strikesand moves along the wear protection element. In this way the usefulnessof the wear protection element which is manufactured as piece goods, isconsiderably increased whereby the manufacturing and storage cost andthus the prime cost of the wearing element are reduced. In theembodiment illustrated the apices of the ridges have been locatedeccentrically in relation to the base surface in such a way that theangles of the two longitudinal side surfaces 12, 13 with the main planeof the wear protection element amount to 35 and respectively. Naturally,other complementary angles also are conceivable as illustrated in theremaining figures in which the apices of the ridges are placedeccentrically in relation to the base surface of the ribs.

As will appear from FIG. 3 the ridges need not be made continuous, butcan also be formed as short ridges 10' arranged in rows, and the ridgesin adjoining rows, as shown in FIG. 3, are preferably offsetlongitudinally in relation to each other to provide a zig-zag pattern. Agreat advantage of providing short separate ridges instead of continuousridges is that the flexibility of the ridges is thereby increasedwithout it being necessary to mix a softer quality of the wear orabrasion resistant rubber proper. Since a harder elastomer quality has ahigher crushing strength than a softer quality, it is thus possible,while retaining the harder elastomer quality and thereby the highercrushing strength, nevertheless to attain increased flexibility and thusfurther increase abrading resistance when the ridges are formed as shortand free-standing elements in accordance with FIG. 3.

The same advantageous effect can be attained if instead of continuousridges 10 one uses possibly truncated, preferably rectangular pyramids14 as projections on the surface of the wear protection element. FIGS.4-6 show a suitable embodiment of an oblique pyramid 14, the apex 15 ofwhich is placed within the base surface of the pyramid in such a waythat the four side surfaces of the pyramid will have different angles ofinclination relative to the base surface. In the embodiment shown, thefour side surfaces make angles of 30, 40, 50 and 60, respectively. withthe base surface. Same as for the short ridges in FIG. 3, the pyramidsmay and should be staggered in relation to each other to provide thebest possible protective effect, retarding effect and possibly agitationeffect.

As already mentioned, the pyramids in FIGS. 4-6 can be formed astruncated pyramids, and it is indicated by broken lines l6 in FIGS. 4-6how the truncation of the pyramids can be done.

FIG. 7 shows an example of how a variant of the wear protection elementillustrated in FIGS. l-3 can be used to protect a sloping or inclinedsurface against abrasion. The wear protection element is here placed onan oblique metal sheet 17 to protect it, the side surface 12 of theridges being turned upwardly in order that the abrading material fallingagainst the wear protection element in the direction of the arrow 18shall strike the rubber surface at an angle of incidence of 85, then toslide downwardly along the wearing element in a cascade-like manner. Inthis instance use is thus made of the wear protection element for theprotection of a surface which is inclined at a 40 angle to thehorizontal, whereas when using the side surface 13 of the ridges one canutilize the wear protection element under otherwise similar conditionsfor the protection of a surface which is inclined at a 60 angle to thehorizontal.

It will be noted that FIGS. 1 and 4-7 each illustrate angles which theopposite faces of the ridges make with the substrate to equal 90, thusbeing complementary, and that the apex angles are accordingly 90. InFIG. 7 the inclined substrate shows material impingement along thedirection 18 which is substantially normal to the impinging faces andsubstantially at grasing or sliding angle to the faces opposite theimpinging faces. When the illustrated wear surface is applied to aconveyor inclined as in FIG. 7, falling material according to 18 strikesthe wear surfaces either nearly perpendicularly or at a sliding angle.The configurations of other Figures present impact angles of theaforesaid 70 90 to material arriving from different characteristicdirections, for maximum wear for a range of angles of material impactupon the general plane of the surface while the opposite faces of thesame ridges will be at sliding angles of substantially 5.

In summary of the present invention discloses that hardened steel orabrasion-resistant materials subjected to impact by abrasive particlesare more durable than resilient faced surfaces for angles of impactbetween about 70 and l 0 to the plane of the surface, but that certainelastomeric materials, including rubber compositions, can be superior tohardened surfaces at impact angles of 70-90 and at grasing angles lessthan 5. Neither material type is superior for all angles. inclinedconveyors for vertical impingement and material passages on whichmaterial arrives in an inclined direc tion have heretofore employedhardened surfaces. It is found they have better durability under impactat angles of 5-l0 to about 70 from the plane of the surface as a whole,but that ridged surfaces comprising resilient covering on the generalplane of the surface are more durable than the hardened surfaces if theangles of impact can be made 70-90 or 05 by selection of ridge geometryto effect the desired angles of impact. Uniform ridges of triangularform are found best, but obviously a single angle of faces relative tothe base surface is not effective for more than a fraction of thepossible angles of impact between 5 or 10 and 70. This inventionprovides a method of manufacturing a resilient surface which can be usedin two different ranges of angle for a continuous ridge extrusion andfour different ranges of angles for a pyramidal set of wear elements.For example, a set of ridge faces at 30 provides for 70 to 90 impact forparticles arriving at inclinations between 10 and 50, while a face(opposite the 30 face) provides for to 90 impact for particles arrivingat inclinations to the base surface between 40 and Thus, by reversingthe formed ridges of 60 and 30 slope relative to the base, the sameridge elements may be attached to the base surface in a manner toprovide 70 to impact throughout all possible angles of inclination ofarriving particles.

Other angles such as 25 and 65 or 40 and 50 are selectable to provide asnearly average perpendicular impact as possible for the best results. Itis also noted that the durability under sliding or grasing impacts ismore critically determined, since sliding impingement at greater than 57 may be no better than the durability of hardened surfaces.Accordingly, the other angles than 30 and 60 have advantages in thatsome material always strikes the ridge faces opposite the intendednearly perpendicular faces. To achieve the full advantage possible inthe use of the invention it is seen that apex angles of about 90 providethe grasing incidence angles for the material sliding faces when theimpact faces are close to normal to the arriving particles.

In a right triangular ridge shape it will be seen that assymetricalfaces are at greater than 45 and less than 45 from the base plane, thefaces presented to the direction of impact being selected to providemore nearly normal impact, the steeper face being presented to impactsat angles less than 45 to the base plane.

Thus a method of preparing a resilient faced impact surface of longerdurability than hardened steel, etc., is provided by attachingunsymmetrical nearly righttriangular ridges to the base surface,selectively according to the surface inclination thereof for verticallyfalling material or according to the angle of arriving material so as topresent impact faces at 70 to 90 and sliding faces as nearly as possibleto grasing incidence, the step of selection and application of theridged elements being according to use. A single form of ridge such as30 and 60 applied according to the foregoing is effective for most usesto produce a product superior to hardened surfaces, and attachingpyramidal elements according to the same principle provides a stillfurther improvement in which the resulting protected surface can move infour directions to closely approach normal and grasing impacts for fourranges of impact angle.

What we claim and desire to secure by Letters Patent l. The method ofpreparing a durable elastomeric surface for receiving abrasive materialfalling thereon having wear resistance enhanced by control of the angleof impact of said material thereon, which surface has lower wearresistance than conventional hardened materials for a range of anglesbetween grazing and perpendicular impact, comprising the steps ofobserving for a particular material flow and surface motion in aninstallation a characteristic angle of impact of a predominant portionof said material upon said surface generally, selecting a set of wearresistant resilient elements having like forward and after faces meetingasymmetrically a ridged vertex, the respective forward and after facesmaking differing angles to the perpendicular to said surface, securingto said surface said elements in mutually parallel relation orientedtransversely to the linear motion of the surface when moving, and to thedirection of impact of material when fixedly inclined, to effectrelative motion between the elements arranged on said surface and motionof said material falling thereon to cause said characteristic angle tolie substantially within degrees of said perpendicular to said forwardfaces.

2. The method of claim 1, said characteristic angle being approximately45 from said surface generally, said after faces then being secured atan angle to the surface between 40 and 50, to cause said material tostike said after faces at a grazing incidence.

3. The method of claim 1 for a said characteristic angle of 45 includingsecuring said forward faces at substantially 45 1 20 from the surfaceand within 20 of perpendicular to said characteristic angle of impact.

4. The method of claim 3 including selecting and orienting elements withsaid after faces within 5 of said angle.

5. The method of claim 1, said observed characteristic angle being atsubstantially 30 1 20 to said surface including arranging said forwardfaces at substantially 20 to said surface.

6. The method of claim 5 wherein said after faces are arranged within 5of said angle 7. The method of claim 1 said observed angle being atsubstantially 60 i 20 to said surface, including arranging said forwardfaces at substantially 30 1 20 to i i i

1. THE METHOD OF PREPARING A DURABLE ELASTOMERIC SURFACE FOR RECEIVINGABRASIVE MATERIAL FALLING THEREON HAVING WEAR RESISTANCE ENHANCED BYYCONTROL OF THE ANGLE OF IMPACT OF SAID MATERIAL THEREON, WHICH SURFACEHAS LOWER WEAR RESISTANCE THAN CONVENTIONAL HARDENED MATERIALS FOR ARANGE OF ANGLES BETWEEN GRAZING AND PERPENDICULAR IMPACT, COMPRISING THESTEPS OF OBSERVING FOR A PARTICULAR MATERIAL FLOW AND SURFACE MOTION INAN INSTALLATION A CHARACTERISTIC ANGLE OF IMPACT OF A PREDOMINANTPORTION OF SAID MATERIAL UPON SAID SURFACE GENERALLY, SELECTING A SET OFWEAR RESISTANT RESILIENT ELEMENTS HAVING LIKE FORWARD AND AFTER FACESMEETING ASYMMETRICALLY A RIDGED VERTEX, THE RESPECTIVE FORWARD AND AFTERFACES MAKING DIFFERING ANGLES TO TTHE PERPENDICULAR TO SAID SURFACE,SECURING TO SAID SURFACE SAID ELEMENTS IN MUTALLY PARALLEL RELATIONORIENTED TRANSVERSELY TO THE LINEAR MOTION OF THE SURFACE WHEN MOVING,AND TO THE DIRECTION OF IMPACT OF MATERIAL WHEN FIXEDLY INCLINED, TOEFFECT RELATIVE MOTION BETWEEN THE ELEMENTS ARRANGED ON SAID SURFACE ANDMOTION OF SAID MATERIAL FALLING THEREON TO CAUSE SAID CHARACTERISTICANGLE TO LIE SUBSTANTIALLY WITHIN 20 DEGREES OF SAID PERPENDICULAR TOSAID FORWARD FACES.
 2. The method of claim 1, said characteristic anglebeing approximately 45* from said surface generally, said after facesthen being secured at an angle to the surface between 40* and 50*, tocause said material to stike said after faces at a grazing incidence. 3.The method of claim 1 for a said characteristic angle of 45* includingsecuring said forward faces at substantially 45* + or - 20* from thesurface and within 20* of perpendicular to said characteristic angle ofimpact.
 4. The method of claim 3 including selecting and orientingelements with said after faces within 5* of said angle.
 5. The method ofclaim 1, said observed characteristic angle being at substantially 30* +or - 20* to said surface including arranging said forward faces atsubstantially 60* + or - 20* to said surface.
 6. The method of claim 5wherein said after faces are arranged within 5* of said angle.
 7. Themethod of claim 1 said observed angle being at substantially 60* + or -20* to said surface, including arranging said forward faces atsubstantially 30* + or - 20* to said surface.